It can be hard at first, as is with anything.
But i have found that it gets easier along the way up to the point where it will not pose a problem anymore.
Porting MT4 code to MT5 is specific for experts and indicators. The goal is to keep MT4 sources working in MT5 without changes or with minimal changes. And it's doable.
For experts you may use the library MT4Orders.
For indicators you may use my approach described in the blogs.